This non-provisional application claims priority under 35 U.S.C. xc2xa7109(a) on patent application No. 2001-312706 filed in Japan on Oct. 10, 2001, which is herein incorporated by reference.
1. Field of the Invention
The present invention relates to an engine control apparatus for a vehicle equipped with an air-conditioning apparatus.
2. Description of the Related Art
In a vehicle equipped with an air-conditioning apparatus (hereinafter, xe2x80x9cair conditionerxe2x80x9d), since an engine drives not only wheels but also a compressor for compressing an air-conditioning refrigerant, a load torque of the compressor acts on the engine. The magnitude of the load torque of the compressor acting on the engine is changed in accordance with an environment (outside air temperature, etc.) in which the air conditioner is used, a passenger""s demand for the air conditioner, and the like during driving of a vehicle.
When the vehicle is driven, a driver operates an accelerator pedal and transmits a demand for a forward/reverse movement of the vehicle to the vehicle. The engine for driving the wheels is controlled in accordance with the amount of operation of the accelerator pedal, and the vehicle responds to the demand of the driver.
Accordingly, when the compressor load is abruptly applied to the engine by turning ON the air conditioner during the traveling of the vehicle, a torque transmitted to the wheels is changed irrespective of an intention of the driver. This gives the driver, a feeling of wrongness (uncomfortableness).
When the vehicle is standing, a feedback control is carried out so that the engine speed is controlled to match a previously set objective idling engine speed. Also here, however, when the compressor load being applied to the engine is abruptly changed, the engine speed is abruptly changed. This causes a delay in response in the feedback control, the engine speed is temporarily changed, and, as a result, a feeling of wrongness is given to the driver.
In view of the above problem, an object of the invention is to provide an engine control apparatus, which can reduce the foregoing driver""s feeling of wrongness in a vehicle equipped with an air-conditioning apparatus.
According to the invention, a larger one of air conditioner loads derived from an outside air temperature and a refrigerant pressure is used as an air conditioner load, and the accuracy of air conditioner load estimation, at the time of an operation start of an air conditioner compressor, is improved.